P0068 - Throttle Body Airflow Performance (PCM)

One of the trouble codes that may appear when the MAF sensor or the ECU has a problem is P0068. This code means that there is a mismatch between the MAF sensor signal and the manifold absolute pressure (MAP) sensor signal. The MAP sensor is another device that measures the air pressure in the intake manifold, which is the part of the engine that distributes the air to the cylinders. The MAP sensor also sends this information to the ECU, and the ECU compares it with the MAF sensor signal. If the two signals do not match, the ECU will detect a problem and set the code P0068.

If you have a car with a modern engine, you may have a device called a mass air flow (MAF) sensor. This sensor measures the amount of air that enters the engine, and sends this information to the engine control unit (ECU). The ECU is the computer that controls how the engine works, and it uses the information from the MAF sensor to adjust the amount of fuel that is injected into the engine. This way, the engine can run smoothly and efficiently, and produce the right amount of power and torque.

However, sometimes the MAF sensor may not work properly, or the ECU may not receive the correct information from the MAF sensor. This can cause the engine to run poorly, and the check engine light to come on. When this happens, the ECU will store a trouble code in its memory, which can be read by a scan tool. A scan tool is a device that connects to your car’s diagnostic port, usually located under the dashboard, and communicates with the ECU. A scan tool can display the trouble code and the freeze frame data, which are the information about the engine’s condition and the parameters at the time of the fault.

In this article, we will explain what causes the code P0068, what symptoms it produces, and how to fix it. We will also give you some additional information, such as the cost, time, and tools needed to fix the code P0068.

What are the causes of DTC code P0068?

There are several possible causes of DTC code P0068, such as:

• Faulty MAF sensor: The MAF sensor may be damaged, dirty, or contaminated, causing it to send wrong or erratic signals to the ECU. This may be due to dirt, debris, oil, or moisture in the sensor, or due to physical damage or wear and tear in the sensor.
• Faulty MAP sensor: The MAP sensor may be damaged, clogged, or disconnected, causing it to send wrong or no signals to the ECU. This may be due to dirt, debris, or vacuum leaks in the sensor, or due to physical damage or wear and tear in the sensor.
• Vacuum leak: A vacuum leak is when there is a hole or a crack in the intake manifold or the hoses that connect it to the engine, causing the air to escape or enter the engine. This can affect the air pressure and the air flow in the engine, and cause the MAF sensor and the MAP sensor to read different values.
• Dirty throttle body: The throttle body is the part of the engine that controls the amount of air that enters the engine, by opening or closing a valve called the throttle. The throttle body may be dirty or carbonized, causing it to stick or malfunction. This can affect the air flow and the air pressure in the engine, and cause the MAF sensor and the MAP sensor to read different values.
• Faulty throttle position sensor (TPS): The TPS is a device that measures the position of the throttle, and sends this information to the ECU. The ECU uses the TPS signal to adjust the fuel injection and the ignition timing. The TPS may be faulty or misaligned, causing it to send wrong or erratic signals to the ECU. This can affect the engine performance and the fuel economy, and cause the MAF sensor and the MAP sensor to read different values.

What are the symptoms of DTC code P0068?

DTC code P0068 may produce some noticeable symptoms, such as:

• Check Engine Light (CEL) illuminated: The CEL is a warning light on the dashboard that indicates a problem with the engine or the emission system. The CEL will come on when the ECU detects a fault or an error in the MAF sensor or the MAP sensor circuit, and will store the code P0068 in its memory. The CEL may also flash or blink, which means that the problem is serious and may damage the engine or the catalytic converter.
• Reduced engine performance: The engine performance may be reduced due to the mismatch between the MAF sensor and the MAP sensor signals. The engine may have less power and torque, and may struggle to accelerate or maintain speed. The engine may also have poor fuel economy, and may consume more gas than usual.
• Rough idle: The engine may idle roughly or unevenly due to the mismatch between the MAF sensor and the MAP sensor signals. The engine may shake, vibrate, or stumble, and may make unusual noises or smells. The engine may also stall or die, especially when cold or warm.
• Engine misfires: The engine may misfire due to the mismatch between the MAF sensor and the MAP sensor signals. A misfire is when the fuel and air mixture in the cylinder does not burn completely or at the right time, causing a loss of power and a jerk in the engine. A misfire may also damage the engine or the catalytic converter, and may trigger other codes, such as P0300, P0301, P0302, etc.

How to fix DTC code P0068?

To fix DTC code P0068, you need to diagnose the problem using a scan tool, and repair or replace the faulty component in the MAF sensor or the MAP sensor circuit. Here are some steps to help you do that:

• Diagnose the problem using a scan tool: You need to use a scan tool to read the code and the freeze frame data from the ECU, and to clear the code and the CEL after the repair. A scan tool is a device that connects to your car’s diagnostic port, usually located under the dashboard, and communicates with the ECU. A scan tool can display the code and the freeze frame data, which are the information about the engine’s condition and the parameters at the time of the fault. A scan tool can also perform some tests and functions, such as checking the voltage and the resistance of the circuit, and activating or deactivating the solenoid. You can buy a scan tool online or at an auto parts store, or you can borrow one from a friend or a mechanic.
• Repair or replace the faulty MAF sensor: You need to locate the MAF sensor, which is usually mounted on the air intake hose, near the air filter. You need to inspect the sensor for any signs of damage, dirt, or contamination, and test it for proper operation. You can use a multimeter to measure the voltage and the frequency of the sensor, and compare it to the specifications in the service manual. You can also use a scan tool to monitor the MAF sensor signal, and see if it changes with the engine speed and load. If the sensor is faulty, you need to replace it with a new one, following the instructions in the service manual. You may also need to clean or replace the air filter, if it is dirty or clogged.
• Repair or replace the faulty MAP sensor: You need to locate the MAP sensor, which is usually mounted on the intake manifold, near the throttle body. You need to inspect the sensor for any signs of damage, clogging, or disconnection, and test it for proper operation.  You can use a multimeter to measure the voltage and the pressure of the sensor, and compare it to the specifications in the service manual. You can also use a scan tool to monitor the MAP sensor signal, and see if it changes with the engine speed and load. If the sensor is faulty, you need to replace it with a new one, following the instructions in the service manual. You may also need to check and fix any vacuum leaks, if they are present.
• Fix a vacuum leak: A vacuum leak is when there is a hole or a crack in the intake manifold or the hoses that connect it to the engine, causing the air to escape or enter the engine. This can affect the air pressure and the air flow in the engine, and cause the MAF sensor and the MAP sensor to read different values. You need to locate and fix the vacuum leak, using a spray bottle, a vacuum gauge, or a smoke machine. You can use a spray bottle filled with water or carburetor cleaner, and spray it around the intake manifold and the hoses, and listen for any hissing sounds or changes in the engine idle. You can use a vacuum gauge to measure the vacuum pressure in the intake manifold, and compare it to the specifications in the service manual. You can use a smoke machine to inject smoke into the intake manifold, and look for any smoke escaping from the leak. If you find a vacuum leak, you need to repair or replace the intake manifold or the hoses, following the instructions in the service manual.
• Clean the throttle body: The throttle body is the part of the engine that controls the amount of air that enters the engine, by opening or closing a valve called the throttle. The throttle body may be dirty or carbonized, causing it to stick or malfunction. This can affect the air flow and the air pressure in the engine, and cause the MAF sensor and the MAP sensor to read different values.  You need to clean the throttle body, using a throttle body cleaner, a rag, and a soft brush. You need to remove the air intake hose and the electrical connector from the throttle body, and spray the cleaner on the throttle valve and the bore. You need to use the rag and the brush to wipe and scrub the dirt and carbon deposits, and make sure the throttle valve can move freely. You need to reattach the air intake hose and the electrical connector to the throttle body, and start the engine. You need to let the engine idle for a few minutes, and then rev it up and down a few times, to reset the idle speed and the throttle position.
• Repair or replace the faulty TPS: The TPS is a device that measures the position of the throttle, and sends this information to the ECU. The ECU uses the TPS signal to adjust the fuel injection and the ignition timing. The TPS may be faulty or misaligned, causing it to send wrong or erratic signals to the ECU. This can affect the engine performance and the fuel economy, and cause the MAF sensor and the MAP sensor to read different values. You need to locate the TPS, which is usually attached to the throttle body, near the throttle valve. You need to inspect the TPS for any signs of damage, wear, or corrosion, and test it for proper operation. You can use a multimeter to measure the voltage and the resistance of the TPS, and compare it to the specifications in the service manual. You can also use a scan tool to monitor the TPS signal, and see if it changes with the throttle position. If the TPS is faulty, you need to replace it with a new one, following the instructions in the service manual. You may also need to adjust or calibrate the TPS, using a scan tool or a screwdriver, if it is misaligned.

Conclusion

DTC code P0068 is a trouble code that indicates a problem with the MAF sensor or the MAP sensor circuit, which affects the operation of the exhaust valves and the performance and efficiency of the engine. This code may be caused by a faulty MAF sensor, a faulty MAP sensor, a vacuum leak, a dirty throttle body, or a faulty TPS, and may produce symptoms such as a check engine light, reduced engine performance, rough idle, fuel economy problems, and engine misfires. To fix this code, you need to diagnose the problem using a scan tool, and repair or replace the faulty component in the MAF sensor or the MAP sensor circuit.

Frequently Asked Questions

Can DTC code P0068 be ignored?

No, DTC code P0068 should not be ignored, as it can affect the performance and efficiency of your engine, and may cause more damage or problems to your engine or the emission system. If you ignore this code, you may experience poor fuel economy, reduced power and torque, rough idle, engine misfires, and increased emissions. You may also fail the emission test, and violate the emission standards and regulations. Therefore, you should fix this code as soon as possible, and prevent it from happening again.

How to prevent DTC code P0068?

To prevent DTC code P0068, you should maintain your engine and its components regularly, and follow the service schedule and the recommendations of your vehicle’s manufacturer. You should also check and replace the MAF sensor, the MAP sensor, the throttle body, and the TPS, if they are worn or damaged. You should also check and fix any vacuum leaks, if they are present. You should also avoid any modifications or alterations to the engine or the emission system, that may affect the MAF sensor or the MAP sensor circuit.

Additional Information

Cost to fix DTC code P0068: The cost to fix DTC code P0068 may vary depending on the vehicle, the location, and the mechanic. However, here are some average estimates of the cost to fix DTC code P0068, based on the parts and labor involved:

• MAF sensor replacement: $100 to $300
• MAP sensor replacement: $50 to $200
• Vacuum leak repair: $50 to $200
• Throttle body cleaning: $50 to $100
• TPS replacement: $50 to $150

Time to fix DTC code P0068: The time to fix DTC code P0068 may vary depending on the vehicle, the location, and the mechanic. However, here are some average estimates of the time to fix DTC code P0068, based on the parts and labor involved:

• MAF sensor replacement: 30 minutes to 1 hour
• MAP sensor replacement: 15 minutes to 30 minutes
• Vacuum leak repair: 30 minutes to 1 hour
• Throttle body cleaning: 15 minutes to 30 minutes
• TPS replacement: 15 minutes to 30 minutes

Tools and supplies needed to fix DTC code P0068: To fix DTC code P0068, you may need some tools and supplies, such as:

• Scan tool
• Multimeter
• Test light
• Spray bottle
• Vacuum gauge
• Smoke machine
• Throttle body cleaner
• Rag
• Soft brush
• Screwdriver
• Wrench
• Electrical tape
• Wire connectors
• Soldering tools
• Service manual
• New MAF sensor
• New MAP sensor
• New TPS
• New gasket or seal

Don’t forget to share it